Human temporal bones will be collected at autopsy and histologically prepared for pathological study. When appropriate, the cochleas and vestibular sense organs will be graphically reconstructed to permit a more accurate assessement of sensory cell deficits. Ganglion cell counts will be done on both the auditory and vestibular nerves and correlated with sensory cell deficits. All pathological changes, including middle ear and bony labyrinth, will be carefully compared to the clinical manifestations of each subject. Attempts will be made to provide new information on the etiology, pathophysiology and, hopefully, the therapy of otologic diseases. Special attention will be given to assessing morphological changes in the vestibular sense organs. Of particular importance will be studies of the vestibular labyrinths of subjects who had vertiginous symptoms in old age.